This invention relates to determining the level or tilt angle of particulate materials in an elongated, rotatable chamber, for example, a rotating oil shale retort.
There are many processes wherein particulate solids are passed through a rotating chamber, for example, an oven, retort, drier, screen, separator, or other similar type cylinder. When such chambers are designed or operated, it is desirable to know the bed depth and/or tilt angle of the solids as they flow through the chamber. Measurements of this type may be made by stopping rotation of the chamber and flow of the solids. The chamber is then physically entered to take the desired measurements; but there are many problems with taking the measurements in this manner. For example, physical access is sometimes difficult or hazardous. In addition, the bed is easily disturbed and the bed tends to slump.